This reminds me of my little sister. I think it's just about how great it is to be around someone who is unafraid to be totally herself (or himself) and therefore gives you the confidence to be yourself. The whole "let's discuss things in confidence / let's be outspoken let's be ridiculous / let's solve the world's problems" is about the conversations you have with someone like that, where you can just be completely comfortable and speak any idea that comes to you and enjoy it along with the other person.
This reminds me of my little sister. I think it's just about how great it is to be around someone who is unafraid to be totally herself (or himself) and therefore gives you the confidence to be yourself. The whole "let's discuss things in confidence / let's be outspoken let's be ridiculous / let's solve the world's problems" is about the conversations you have with someone like that, where you can just be completely comfortable and speak any idea that comes to you and enjoy it along with the other person.